Hello fellas!
The "latecommers" have received a PM from me regarding the Form which needs to be filled out. You have time to pay till 26.05.14. Please choose only PayPal as Payment Option in the Form.
Please send me the wanted quantities of the DAC and PSU PCB over PM.
So please provide your Informations through the Form as fast as possible so I can send you the PayPal Payment requests.
Thanks and nice weekend to ya all!
Ron.
The "latecommers" have received a PM from me regarding the Form which needs to be filled out. You have time to pay till 26.05.14. Please choose only PayPal as Payment Option in the Form.
Please send me the wanted quantities of the DAC and PSU PCB over PM.
So please provide your Informations through the Form as fast as possible so I can send you the PayPal Payment requests.
Thanks and nice weekend to ya all!
Ron.
Daniel, can I just check a couple of things regarding the PSU boards please - you said they were designed to be flexible...
Apart from powering the Curryman DAC, I have ordered additional PSU boards to power a small tube headphone amplifier that will be fed by the DAC. Each amplifier module requires 330mA @6-6.3V DC for the filaments and +/-15V DC @165mA for the power rails.
For the Filament supply I will use one of the larger PSU board and configure it for +/-6.3V DC. I will order the Block Transformer 10VA 2*9V 2*555mA transformer. I believe I will need to change the resistor in the CRC because of the higher current and voltage (compared with the smaller 5V supply). What do you think? Any thoughts on a suitable r value? Also, I would prefer to fix the output voltage rather than use an adjustable preset in order to avoid drift; what value resistor would I need to replace the zeneer with or is there a better way?
For the power rails I will build the larger PSU boards as per the BOM except, again, I think I may need to change the resistor in the CRC as the higher current will lose volts and the dropout across the regulator might get a bit marginal. What do you think?
I think these uses are all feasible with the onboard transfomers, though they may get a little warm so there will be ventilation - I already have a chassis I want to make use of so space is a little constrained for off board transformers. The headphone amplifier will be for casual/office use so compromises are OK. BTW, I do plan to heatsink the regulator chips.
Thanks
Ray
Apart from powering the Curryman DAC, I have ordered additional PSU boards to power a small tube headphone amplifier that will be fed by the DAC. Each amplifier module requires 330mA @6-6.3V DC for the filaments and +/-15V DC @165mA for the power rails.
For the Filament supply I will use one of the larger PSU board and configure it for +/-6.3V DC. I will order the Block Transformer 10VA 2*9V 2*555mA transformer. I believe I will need to change the resistor in the CRC because of the higher current and voltage (compared with the smaller 5V supply). What do you think? Any thoughts on a suitable r value? Also, I would prefer to fix the output voltage rather than use an adjustable preset in order to avoid drift; what value resistor would I need to replace the zeneer with or is there a better way?
For the power rails I will build the larger PSU boards as per the BOM except, again, I think I may need to change the resistor in the CRC as the higher current will lose volts and the dropout across the regulator might get a bit marginal. What do you think?
I think these uses are all feasible with the onboard transfomers, though they may get a little warm so there will be ventilation - I already have a chassis I want to make use of so space is a little constrained for off board transformers. The headphone amplifier will be for casual/office use so compromises are OK. BTW, I do plan to heatsink the regulator chips.
Thanks
Ray
Ron, not sure how it's going with the group buy but those on the waiting list had a chance to order so presumably not everyone who initially expressed interest actually followed through with a payment. Anyway, if you end up with some PSU boards on your hands let me know and I'll take a couple more - always useful to have such things in the spares box.
Ray
Ray
Ditto,
I had tried to modify my order after receiving the paypal request, without luck. So I did the payment for the inital quantity.
Just in case I'd happily take 1 DAC more and a couple of PSU boards of well if possbile/leftovers/no reveived payment etc. ...
Cheers,
Max
Damn. So many PMs.
The initial Group Buy spreadsheet is locked so nobody can change it anymore after closing the GB officially. Daniel and myself are maintaingin a private spreadsheet with all your data.
There are some (about 3-5) DACs free to order. And maybe 1-2 PSU PCBs.
The order from miniDSP will be initiated this week.
The bad thing about PayPal is that I can not pay with the money I got for 21days after payments. So I need to pay with my private/own money so you get all your DACs and PSU PCBs as soon as possible.
"PayPal, Oh how I love thou
The initial Group Buy spreadsheet is locked so nobody can change it anymore after closing the GB officially. Daniel and myself are maintaingin a private spreadsheet with all your data.
There are some (about 3-5) DACs free to order. And maybe 1-2 PSU PCBs.
The order from miniDSP will be initiated this week.
The bad thing about PayPal is that I can not pay with the money I got for 21days after payments. So I need to pay with my private/own money so you get all your DACs and PSU PCBs as soon as possible.
"PayPal, Oh how I love thou
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Dear Ray and all others,
It’s indeed quite easy to adapt the board for other voltages/currents. I am currently writing an assembly instruction which will cover those options. Each buyer will get such instructions.
Calculation of the filter R is quite straight forward. Just calculate the voltage you’d like to drop and use ohms law. E.g. in your case with 6.3V output and 9V transformer: 9V * 1.4 [rectification] = 12.6V – (6.3V + 3V) [output voltage + dropout voltage for regulator] = 3.3V -> R = 3.3V / 330mA = 10 Ohms. Always good to have some margin and thus take the next lower value, e.g. 8.2 Ohms ;-) Also keep an eye on power dissipation (2W resistor should be OK in this example).
With respect to fixed output voltage: I’d use a simple resistor divider as per the LM317/337 datasheet if you are looking for voltages around 6V. Zener diodes in this voltage range (4-6V) are much noisier. Alternatively you can use a cascade of LEDs (desired output voltage – 1,25V = forward voltage of LED cascade) as used for the smaller single voltage PCB, however you’d have to use some free style wiring here.
Always good to have enough ventilation as it is to apply some heatsinks to the regulators. With low currents (<100mA, e.g. 1 or two DACs) heat sinking is not really necessary but for higher currents it is essential. Again the datasheet is your friend
E.g. in your case:
It’s indeed quite easy to adapt the board for other voltages/currents. I am currently writing an assembly instruction which will cover those options. Each buyer will get such instructions.
Calculation of the filter R is quite straight forward. Just calculate the voltage you’d like to drop and use ohms law. E.g. in your case with 6.3V output and 9V transformer: 9V * 1.4 [rectification] = 12.6V – (6.3V + 3V) [output voltage + dropout voltage for regulator] = 3.3V -> R = 3.3V / 330mA = 10 Ohms. Always good to have some margin and thus take the next lower value, e.g. 8.2 Ohms ;-) Also keep an eye on power dissipation (2W resistor should be OK in this example).
With respect to fixed output voltage: I’d use a simple resistor divider as per the LM317/337 datasheet if you are looking for voltages around 6V. Zener diodes in this voltage range (4-6V) are much noisier. Alternatively you can use a cascade of LEDs (desired output voltage – 1,25V = forward voltage of LED cascade) as used for the smaller single voltage PCB, however you’d have to use some free style wiring here.
Always good to have enough ventilation as it is to apply some heatsinks to the regulators. With low currents (<100mA, e.g. 1 or two DACs) heat sinking is not really necessary but for higher currents it is essential. Again the datasheet is your friend
E.g. in your case:
- Calculate power dissipation: P_d = ((V_in-V_out) x I_load) + (V_in * I_g), e.g. in your example roughly P_d = 4V * 330mA + 9.3V * 12.5mA ~ 1.5W.
- Calculate max. temperature rise: T_rise = T_junction – T_ambient. Incl. some savety margin let’s say T_rise = 100°C – 50°C = 50°C (or Kelvin)
- Overall thermal resistance must be lower than ɵ_JA = T_rise / P_d, here 36 K/W. TO220 has a thermal resistance of 50K/W as per the datasheet and thus a heatsink is necessary! If P_d is lower than 1W no heatsink is required.
- Heatsink calculation: ɵ_HA < (ɵ_JA – (ɵ_CA + ɵ_JC)), here 36 K/W – (~1 K/W + 4 K/W) = 31 K/W. Therefore choose a heatsink with Rthk < 31 K/W.
Thank you Daniel, that's very useful and your user guide will be a good asset.
I've been trying to work it out for myself so I'm reassured that I came up with 10R for the CRC resistor...
The boards are flexible in other ways too; if you need more current than the 3.2VA trafo on the small board can deliver you can populate just one side of the larger board to get 5VA and with a little hard wiring it is possible to connect the two secondaries on the larger board to get a 10VA trafo to power one side of the larger board, which at 5V will give you up towards 1A - I'm planning to do that to power a BeagleBone
Ray
I've been trying to work it out for myself so I'm reassured that I came up with 10R for the CRC resistor...
The boards are flexible in other ways too; if you need more current than the 3.2VA trafo on the small board can deliver you can populate just one side of the larger board to get 5VA and with a little hard wiring it is possible to connect the two secondaries on the larger board to get a 10VA trafo to power one side of the larger board, which at 5V will give you up towards 1A - I'm planning to do that to power a BeagleBone
Ray
Dear Ray and all others,
It’s indeed quite easy to adapt the board for other voltages/currents. I am currently writing an assembly instruction which will cover those options. Each buyer will get such instructions.
Calculation of the filter R is quite straight forward. Just calculate the voltage you’d like to drop and use ohms law. E.g. in your case with 6.3V output and 9V transformer: 9V * 1.4 [rectification] = 12.6V – (6.3V + 3V) [output voltage + dropout voltage for regulator] = 3.3V -> R = 3.3V / 330mA = 10 Ohms. Always good to have some margin and thus take the next lower value, e.g. 8.2 Ohms ;-) Also keep an eye on power dissipation (2W resistor should be OK in this example).
With respect to fixed output voltage: I’d use a simple resistor divider as per the LM317/337 datasheet if you are looking for voltages around 6V. Zener diodes in this voltage range (4-6V) are much noisier. Alternatively you can use a cascade of LEDs (desired output voltage – 1,25V = forward voltage of LED cascade) as used for the smaller single voltage PCB, however you’d have to use some free style wiring here.
Always good to have enough ventilation as it is to apply some heatsinks to the regulators. With low currents (<100mA, e.g. 1 or two DACs) heat sinking is not really necessary but for higher currents it is essential. Again the datasheet is your friend
E.g. in your case:
kind regards, Daniel
- Calculate power dissipation: P_d = ((V_in-V_out) x I_load) + (V_in * I_g), e.g. in your example roughly P_d = 4V * 330mA + 9.3V * 12.5mA ~ 1.5W.
- Calculate max. temperature rise: T_rise = T_junction – T_ambient. Incl. some savety margin let’s say T_rise = 100°C – 50°C = 50°C (or Kelvin)
- Overall thermal resistance must be lower than ɵ_JA = T_rise / P_d, here 36 K/W. TO220 has a thermal resistance of 50K/W as per the datasheet and thus a heatsink is necessary! If P_d is lower than 1W no heatsink is required.
- Heatsink calculation: ɵ_HA < (ɵ_JA – (ɵ_CA + ɵ_JC)), here 36 K/W – (~1 K/W + 4 K/W) = 31 K/W. Therefore choose a heatsink with Rthk < 31 K/W.
@riddim
Sorry to say that but there are none left anymore..
So to all of you :
There are no DACs and PSU PCBs left.
There are about 4 PSU PCBs left from a previous order Daniel made. But they are green and had a little failure which was corrected by him. These boards are working like the black ones will.
Sorry to say that but there are none left anymore..
So to all of you :
There are no DACs and PSU PCBs left.
There are about 4 PSU PCBs left from a previous order Daniel made. But they are green and had a little failure which was corrected by him. These boards are working like the black ones will.
So far so good then Ron; you've cleared the shelves and, hopefully, won't be out of pocket... Thanks to you and Daniel for your efforts getting us this far.
I hope you're finding time to prepare for your forthcoming exams as well, as I recall they're not that far away now, and I hope you can get the rest of the GB out of the way before you sit them?
Cheers
Ray
So I thought about the shipping.
There are some which have ordered some of the DACs. So the total sum exeeds 80€.
If you will have a better feeling your package to be sent with ensurance and tracking I will give you the option to pay the additional 6,49€ + PayPal Fee through PayPal and I will send you the Package with ensurance and tracking.
I need to say that I will do the best to pack your order best I can. PSU PCBs will be sent in protected envelopes and the currymanDACs will be send in Packages. (I have collected many packages the last month ). I will Print out your Provided Addresses and put them in the Envelopes and packages so in case the envelope gets damaged or the package gets damaged in a way so the address sticker on the package is not readable anymore they have your addresses on the printed out paper in the package.
I will also make a picture from every package and will send it to you email addresses.
So I need to say this: I will do my best packing your orders, but there can alway happen some things on the way to your place. Please don't make me responsible for that. I will offer you the possibility to pay for a shipping with ensurance and tracking. This is totally optional but my offer to you so you have a better feeling regarding the shipping for your expensive order!
Please PM me if you want shipping with ensurance and tracking. This is only for those who ordered min. one currymanDAC
Btw.
Guess whats inside here,warm and tidy waiting to be shipped to germany and finally to you! ^^ (image provided by miniDSP)
There are some which have ordered some of the DACs. So the total sum exeeds 80€.
If you will have a better feeling your package to be sent with ensurance and tracking I will give you the option to pay the additional 6,49€ + PayPal Fee through PayPal and I will send you the Package with ensurance and tracking.
I need to say that I will do the best to pack your order best I can. PSU PCBs will be sent in protected envelopes and the currymanDACs will be send in Packages. (I have collected many packages the last month ). I will Print out your Provided Addresses and put them in the Envelopes and packages so in case the envelope gets damaged or the package gets damaged in a way so the address sticker on the package is not readable anymore they have your addresses on the printed out paper in the package.
I will also make a picture from every package and will send it to you email addresses.
So I need to say this: I will do my best packing your orders, but there can alway happen some things on the way to your place. Please don't make me responsible for that. I will offer you the possibility to pay for a shipping with ensurance and tracking. This is totally optional but my offer to you so you have a better feeling regarding the shipping for your expensive order!
Please PM me if you want shipping with ensurance and tracking. This is only for those who ordered min. one currymanDAC
Btw.
Guess whats inside here,warm and tidy waiting to be shipped to germany and finally to you! ^^ (image provided by miniDSP)
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Hi there, just to keep you updated:
DHL tried to deliver the Package from miniDSP this morning but I was at the University. I rearranged a delivery for Friday when I am at home in the morning.
We just need to wait for the PSU PCBs.
The Package needed only one week from Hong Kong to Hamburg in Germany including the time it was kept for customs. I will make a Picture when the Package arrives.
What I also want to say is that the people at miniDSP are really kind and friendly. This was my first contact with miniDSP and all went really fine even exceeding my expectations. They even sent the Package before I paid. In short: The service is really awesome. (I was not forced to say this, this is my own experience with miniDSP).
Can not wait to finally send it to you and maybe see what projects you are realizing with the currymanDAC and the PSU.
So long, cheers
Ronald!
DHL tried to deliver the Package from miniDSP this morning but I was at the University. I rearranged a delivery for Friday when I am at home in the morning.
We just need to wait for the PSU PCBs.
The Package needed only one week from Hong Kong to Hamburg in Germany including the time it was kept for customs. I will make a Picture when the Package arrives.
What I also want to say is that the people at miniDSP are really kind and friendly. This was my first contact with miniDSP and all went really fine even exceeding my expectations. They even sent the Package before I paid. In short: The service is really awesome. (I was not forced to say this, this is my own experience with miniDSP).
Can not wait to finally send it to you and maybe see what projects you are realizing with the currymanDAC and the PSU.
So long, cheers
Ronald!
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